Duplex sewing machine



March 2, 1937..

D. w. KLAU DUPLEX SEWING MACHINE 5 Sheets-Sheet 2 INVENT flaVid Filed Feb. 24, 1933 B V gal ATTORNEY all:nuuuuuuuunilin D. W. KLAU DUPLEX- SEWING MACHINE March 2, 193 7.

3 SheetSheet 3 1 Filed Feb. 24, 1933 INVENTOR flavid WKlau. 2/ BY Patented Mar. 2, 1937 UNITED STATES PATENT OFFICE 2,972,113 DUPLEX SEWING MACHINE David W. Klau, New York, N. Y. Application February 24, 1933, Serial No. 658,367

1 Claim.

This invention relates to a duplex sewing maof stitching simultaneously.

While this invention is particularly adapted for the hemming of the opposite parallel sides of a roller shade or the like, it will be obvious that it may be employed in other relations as well.

The present invention is in the nature of an improvement upon the machines disclosed and claimed in my patents numbered 1,578,324, March 30th, 1926, and 1,608,944, November 30th, 1926.

An object of the present invention is to provide improved means of supporting and connecting two reversely positioned sewing machine elel5 mens for simultaneous operation from a single drive shaft.

A further object is to provide an improved supporting frame for the sewing machine elements, and to provide improved means for adjusting the 20 position of one or both of the sewing machine elements along said supporting frame.

A further object is to provide improved looking means for holding the sewing machine elements in adjusted position.

25 A further object is to provide improved cutting means for the thread which extends from one window shade or the like to another.

A further object is to improve generally the practicability, efficiency, appearance and the ease and simplicity of operation of the machine as a whole.

Other objects and aims of the invention, more or less specific than those referred to above, will be in part obvious and in part pointed out in the 5 course of the following description of the elements, combinations, arrangements of parts and applications of principles constituting the invention; and the scope of protection contemplated will be indicated in the appended claim.

40 In the accompanying drawings which are to be taken as a part of this specification, and in which I'have shown merely a preferred form of embodiment of the invention:-

Fig. 1 is a top plan view of a machine con- 45 structed in accordance with this invention.

Fig. 2 is a vertical sectional View substantially upon the plane of line II-II of Fig. 1 and looking in the direction of the arrows on said line.

Fig. 3 is a similar sectional view of the upper 50 portion of the machine, said section being taken approximately upon the plane of line III-III of Fig. l and looking in the direction of the arrows on said line.

Fig. 4 is a vertical transverse sectional view 56 substantially upon the plane of line lV--IV of Fig. l and looking in the direction of the arrows on said line.

Fig. 5 is a, similar sectional view taken substantially upon the plane of line V-V of Fig. l and looking in the direction of the arrows on said 5 line.

Fig. 6 is a vertical transverse sectional view taken substantially upon the plane of line VI--VI of Fig. 1 and looking in the direction of the arrows on said line. 10

Fig. '7 is a fragmentary perspective view il1us-' trating a portion of the thread cutting mechanism and associated parts.

Fig. 8 is an enlarged vertical fragmentary sectional view of the thread cutting mechanism and associated parts, and i Fig. 9 is a fragmentary deta'l sectional view illustrating the connection between one of the sewing machine elements and the common drive shaft.

Referring to the drawings for describing in detail the exemplary structure which is illustrated therein, the reference character L indicates a main frame comprising a top or table portion having suitable legs as l-I.

The top or table portion illustrated consists of two longitudinal members as 2 and 3, each of right angular cross section, ordinary commercial angle irons as illustrated being well adapted to the purpose. These longitudinal members are arranged with vertical flanges depending and spaced apart, the horizontal flanges projecting outwardly in opposite directions. End connecting members as 4 and 5 extend between and connect the longitudinal members 2 and 3, said 5 end connecting members being of channel shape as most clearly illustrated in Fig. 5, the opposite flange portions as 6-6 resting against the inner surfaces of the vertical flanges of the longitudinal members and being bolted thereto, preferably by the same bolts as 1-4 which serve to attach the legs |-l.

Fixed to the inner surfaces of. the vertical flanges of the longitudinal members 2 and 3 respectively are strips 8 and 9, the upper longitudinal edge surfaces of which are spaced downwardly a slight distance below the upper surface of the horizontal flanges of said longitudinal members thereby to form angle recesses as I0 and i I which collectively define a run-way longitudinally of the machine adapted to slidably receive and support the two sewing machine elements as G and H, said sewing machine elements having bed plates as l2 and I3 respectively, the

opposite longitudinal edge portions of which rest slidably in the angle recesses l0 and H so that said machines may be slid easily toward and away from each other along the run-way.

As a convenient and practical means by which to slide the machines manually at will toward and away from each other along the run-way each machine carries a hand rotatable spindle l4 projecting downwardly below the main table portion of the machine and having fixed to its upper end a small pinion IS the teeth of which constantly mesh the teeth of a rack bar I6 fixed to one of the longitudinal members as 2, being preferably formed as a part of, or fixed to, the strip 8. At their lower ends these spindles each carry a hand wheel as I! by which the spindles and pinions may be rotated to thereby cause the pinions to walk along the rack bar and to thus slide the machines in one direction or the other according to the direction of rotation of the hand wheels.

The spindles I4 stand in a substantially vertical position and each is rotatably mounted in a bearing sleeve as |8 formed as a part of the respective sewing machine.

As a convenient meansby which to hold the machines against accidental sliding movement along the table each of the spindles i4 is provided with a. locking handle as 9 by which to lock it against possibility of rotary movement within its sleeve l8. The hand wheels ll are feathered onto the spindles |4 so as to be readily slidable longitudinally .of said spindles while yet rotatable as one with said spindles. And the spindles project downwardly below the hand wheels, being threaded as at 20, and the locking handles H) are threaded thereonto as indicated in Fig. 4.

By turning the locking handle upwardly along the threads 20 it operates to draw downwardly upon the spindle and press upwardly against the hand wheel, thereby constituting the pinion and hand wheel as clamp elements against the upper and lower ends respectively of the sleeve I8 thus locking the spindle and sleeve together so that no rotary movement of the pinion is possible until the locking handle is rotated to release these clamping parts from their frictional grip upon the sleeve.

The interlocking engagement of the pinions with the teeth of the rack bars will of course serve to prevent any sliding movement of. the machines without accompanying rotary movement of said pinions.

Extending longitudinally of the table parallel with the longitudinal members 2 and 3, and intermediate said members, is a single drive shaft 2| used for simultaneously driving the two machines G and H. This shaft is rotatably supported by its opposite end portion in adjustably mounted bearings as 2222 and carries a pulley or other suitable means as 23 by which it is rotated from a suitable motor or other source of power as 24, the connections between the motor 24 and the shaft being through a belt or the like as 25 and a clutch device as 26 under control of the operator by means of. a foot tre-adle or other control element as 21.

Feathered onto the shaft 2| is a pair of bevel gears 28 and 29, said gears being connected with the respective machines G and H to slide back and forth along the shaft at will in accordance with the position of the respective machines longitudinally of the table. Any suitable means may be employed for connecting the bevel gears with the machines, that illustrated in the drawings Fig. 9 being suitable and being illustrated as an example. According to the arrangement shown in Fig. 9, the gears, as 28, are carried by sleeves as 30 rotatably mounted in downward extending parts as 3| of the machines and feathered onto the shaft, the gears having opposite shoulder parts as 32 and 33 engaging the extensions 3| to hold the gears for movement with the machines without interfering with the easy rotary movement of the gears at all times.

Each of the machines G and H includes the usual main body part as 34 within which is carried the usual needle operating mechanism and other features common to sewing machine construction. Extending from this main body part is a bevel gear 35 and this bevel gear is connected with the respective adjacent bevel gears 2829 by a shaft as 35 having bevel gears as 37-38 at its opposite ends standing in constant mesh with the gears 35 and 28 of the machine G and 35 and 29 of the machine H.

Suitable protecting housings as 39 surround the gears 35 and 37 so as to guard and protect said gears and prevent possible injury to the operator.

The sewing machines G and H are reversally positioned, that is they are arranged so that they face toward each other, and it will be noted that owing to this relatively reversed position of the two machines the driving connections between the gears 35 and the single drive shaft 2|, as just described, differ so that the gears 35 of the two machines rotate in opposite directions, this being accomplished simply by making the gears 28 and 35 of the machine G to stand both at the same; side of the vertical axis of shaft 36 while making the gears 29 and 35 to stand .on opposite sides of the vertical axis of the shaft 36 in machine H.

Through the medium of these connections the two sewing machines are thus adapted for running lines of stitching simultaneously in the same direction along a single piece of goods, as for instance a piece of window shade cloth as 40, moving transversely across the table as indicated in Fig. 1.

The shade material 40 may be carried as a roll,

as indicated at 4|, inbrackets as 42 and 43 fixed to and movable with the sewing machines G and H respectively, said brackets extending forwardly beneath the longitudinal table member 2 and being suitably curved to conveniently support the roll 4| of material to be attached, the material being thus conveniently held so that it may unwind from the roll and pass directly beneath the stitching heads of the two sewing machines.

If the sewing machines be adjusted toward or away from each other, as for the purpose of working upon goods of different widths, the brackets 42 and 43, being carried by said sewing machines respectively, would likewise be moved stoward or away from each other automatically and thus made to properly accommodate and support the different length rolls of goods by the same operation of the hand wheels I! as adjusted the sewing machines.

A particular purpose of the present invention is that of stitching hems as 4444 at the op posite longitudinal edge portions of window shades and the like. In this instance a number of separate pieces of window shade material are wound into a single roll 4|. passed beneath the stitchingheads of the sewing machines G and H the operator feeds along behind it the next piece from. the roll 4|, and this operation is repeated as the stitching of the successive pieces is completed.

Always a space of an inch or two occurs be- After one piece has 1 tween the succeeding pieces of window shade ma terial. The stitching threads continue across this space and must be severed so that the hemmed shades may be separately handled in the subsequent operations of completing them.

As a suitable means for quickly, simultaneously and surely cutting the stitching threads between successive window shades the present invention proposes a pair of thread cutters as -45 constructed and operated as follows: The two thread cutters 45 are identical. Each includes a body portion 45 having a pendant intermediate web part as 4'! to which is attached a sharp cutting blade as 48, for instance a safety razor blade. A carrying stem 49 projects downwardly through a slot as 5!? formed longitudinally through the horizontal flange of the table forming member 3 and into fixed sliding connection with a horizontal bar 5| mounted for parallel vertical movement in the space beneath the horizontal flange of said table member, the two thread cutters being mounted upon the same bar 5|, one adjacent one end of said bar and the other adjacent the opposite end of said bar, and the arrangement being such that a downward vertical movement of the bar will cause the cutting blades 48 of the two thread cutters to move simultaneously downwardly through the slot 5!), as illustrated particularly in Figs. 3 and 8.

Two separate presser feet as 52 and 53 are carried by the body 46 one at the forward side of the cutting blade and the other at the rear side of the cutting blade. These presser feet are yieldably mounted, as by being carried upon supporting rods as 54-54 vertically slidable in the body 46, compression springs as 55 engaging about said rods and serving to urge the presser feet downwardly but affording opportunity for continued downward movement of the body when downward movement of the presser feet is obstructed by engagement against the top horizontal surface of the frame or table member 3.

Suitable connecting members, as indicated at 56-56, extend between the sewing machines. G

v and H respectively and the adjacent thread cutters operable to cause sliding movement of the thread cutters along the horizontal bar 5| corresponding with all longitudinal adjustments of the sewing machines along the table, and the disposition of the thread cutters is such that the cutting blades and the presser feet of the thread cutters stand always in alignment with the stitching threads as said threads issue from the sewing machines respectively and move along with the work, the position of the two thread cutters with respect to the two sewing machines and the work being substantially as illustrated in Fig. 1.

Suitable guide members 51 are comprised in the sewing machines adapted to be engaged by marginal portions of the passing work so as to guide the work with respect to the stitching needles and the thread cutters.

The horizontal bar 5! is ijoatingly supported to move readily up and. down along a pair of guide rods 58-58 which extend loosely through apertures 59--59 formed in the opposite end portions of the bar, springs as 60-450 being carried by the guide rods positioned beneath the horizontal bar and other, and relatively lighter, springs 6l-6I being carried by the guide rods positioned above the horizontal bar, all of said springs pressing yieldingly against the bar and serving collectively to hold the bar in a normal relatively elevated position.

A foot treadle as 62 is provided and a suitable connecting frame as 63 extends between this treadle and the opposite end portions of the horizontal bar in such wise as to cause a horizontal downward movement of the bar bodily against the compression of the springs 60-435 whenever the treadle 62 is depressed, the shape of the connecting frame 62 and the manner of attaching it to the horizontal bar being such as to apply equal downward pull against the opposite end portions of the horizontal bar, and to leave the intermediate portion of the horizontal bar free and unobstructed for longitudinal sliding movement of the thread cutters at the will of the operator.

The manner of operating the thread cutters is simple: The operator, noting that the work has moved along so that the end of a completely stitched piece of work has just passed the thread cutters and that only the loose threads extending from this finished piece to the next succeeding piece are stretched across the slots 50 beneath the cutting blades 48 and presser feet 52 and 53, suddenly presses down the foot treadle 62 so as to move the two thread cutters simultaneously downwardly. The presser feet normally stand in a horizontal plane slightly below the cutting edge of the cutting blade so that as the thread'cutters move downwardly said presser'feet first engage the threads and operate to clamp the threads at opposite sides of slot 50 againstthe top surface of the table member 3 thereby gripping and holding the threads stretched across the slot 50. The continued downward movement of the cutting blade causes the blade to pass through and sever the threads where the threads span the slot.

The severing of the threads at opposite sides of the work is thus accomplished instantly and with perfect reliability, and the operation is fully under the control of the operator.

Instantly the foot pressure is moved from treadle 62 the springs 60B0 snap horizontal bar 50 and consequently the two thread cutters upward again to their normal position free of the passing work, the springs 6l6| serving at this time to cushion the upward movement of the horizontal bar.

While the mechanism herein shown and described shows both of the sewing machines G and H, and associated parts, to be adjustably movable longitudinally of the table, it will be understood that if desired one of the machines and its associated parts may remain stationary, and even be made without ability for adjustment if desired, the other sewing machine alone, with its associated parts, being in that case moved to provide the requisite spacing of the two sewing machines longitudinally of the table.

The entire mechanism is simple, substantial, durable and practical. The operator has merely to adjust one or both of the sewing machines by means of the hand wheel |1-l'l to properly operate upon the particular width of goods.

to be hemmed, then looking the sewing machine or machines as by means of the locking handles l9, press the foot treadle 2'! to apply the requisite power for operating the two sewing machines, and proceed to feed the work from roll 48 across the table through the guide devices 5757 and periodically snapping down and reing carried by and movable with the respective sewing machines, they not only guide the work accurately with respect to the two sewing needles and the two thread cutters, but they also always insure that the roll 4| of the Work is properly centered longitudinally with respect to the two brackets 42 and 43 which support the roll of work.

The top surface of the table member 3, where the presser feet engage, as at (54, may be roughened if desired, and the under surfaces of the presser feet' may be matingly roughened, or may be formed of a yielding material such as rubber, so as to more efiiciently frictionally grip and hold the threads against endwise sliding when the cutting blades are pressed against the threads.

As many changes could be made in this construction without departing from the scope of the invention as defined in the following claim, it is intended that all matter contained in the above description, or shown in the accompanying drawings, shall be interpreted as illustrative only and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:-

In a duplex sewing machine adapted for the making of two parallel lines of stitching lengthwise of a piece of work, the combination including two separate sewing machines spaced apart, a supporting table upon which said machines are mounted so as to be relatively movable adjustably toward and away from each other, a single drive shaft carried by said table extending common to said sewing machines, means for rotating said shaft, connections between said shaft and said sewing machines for operating said sewing machines simultaneously by power derived from said shaft and regardless of adjustable movement of the sewing machines toward and away from each other, a rack bar carried by the table extending longitudinally thereof, and means carried by at least one of said sewing machines engaging said rack bar manually operable to move the mentioned sewing machine along the table, said means including a spindle rotatably mounted in a bearing part of the mentioned sewing machine, a pinion fixed to said spindle at one end of said bearing part, a hand wheel slidably connected with the spindle at the opposite end of said bearing part but fixed to rotate with the spindle so that rotation of said hand wheel will cause the pinion and consequently the mentioned sewing machine to travel along the rack bar, and a member engaging the spindle beyond said hand wheel manually operable to press the hand wheel and the pinion in opposite directions against said bearing part of the sewing machine thereby to lock the pinion, and hence the sewing machine, against travel along said rack bar.

DAVID W. KLAU. 

